ARID1A‐SIN3A drives retinoic acid‐induced neuroblastoma differentiation by transcriptional repression of TERT

Abstract

Aggressive, high‐risk neuroblastoma (NB) exhibits an immature differentiation state, profound epigenetic dysregulation and high telomerase activity. It has been suggested that aggressive NB may be treatable by inducing differentiation whereas therapeutic targeting of telomerase is under investigation for multiple cancer types. While epigenetic regulation of the telomerase reverse transcriptase (TERT) promoter has been described in high‐risk NB, the exact molecular mechanisms are still not completely understood. Here we used quantitative real‐time polymerase chain reaction (PCR), chromatin immunoprecipitation qPCR, quantitative telomeric repeat amplification protocol, and immunoblot techniques to investigate epigenetic regulation of TERT in wild‐type and genetically modified NB cell lines. We demonstrated that TERT expression is reduced during 13‐cis retinoic acid‐induced NB differentiation and that this inversely correlated with increased expression of AT‐rich interaction domain 1A (ARID1A), a subunit of the SWItch/sucrose nonfermentable chromatin remodeling complex. We showed that ARID1A directly caused suppression of TERT and was reliant on DNA binding and co‐occupancy of the TERT promoter by the SIN3 transcription regulator family member A (SIN3A) repressor complex allowing NB differentiation to proceed. Finally, using data from NB patient cohorts, we reported a significant correlation between low ARID1A expression, elevated expression of TERT, and poorly differentiated, high‐risk NB. These results provide insights into a key epigenetic pathway responsible for modulating TERT‐driven NB progression, which could represent a target for therapeutic intervention.

Neuroblastoma and the epigenome

“…Promoter occupancy studies showed that ARID1A through SIN3A suppressed the expression of TERT, thus resulting in increased differentiation of NB cells. Patient data showed an inverse correlation between ARID1A and TERT expression, indicating a putative tumor suppressor role for ARID1A in NB [194].…”

Collagen XI Alpha 1 (COL11A1) Expression in the Tumor Microenvironment Drives Neuroblastoma Dissemination

“…Each sample was scored and evaluated separately by 2 oncology pathologists. Immuno-scoring was used as per our previous study 12 to analyze both staining intensities and the proportion of anti‐COL11A1 (#HPA052246, Sigma‐Aldrich) and anti-Vimentin (SAB4503083, Sigma‐Aldrich) positive cells. Staining intensity was scored as 1 (weak), 2 (moderate), or 3 (strong).…”

“…NB samples were obtained from our NB cohort 12 in which clinical, biological and survival data has been collected for 5 years. 13 This study was approved by the Ethics Institutional Review Board of the University of Medicine and Pharmacy in Ho Chi Minh City, Vietnam (N0.UMP-2013).…”

“…Each sample was scored and evaluated separately by 2 oncology pathologists. Immuno-scoring was used as per our previous study 12 5 categories: 1 (<5%), 2 (5%-25%), 3 (26%-50%), 4 (51%-75%), or 5 (>75%). Values for both parameters were multiplied to generate a final immunohistochemistry score.…”

ARID1A maintains transcriptionally repressive H3.3 associated with CHD4-ZMYND8 chromatin interactions

“…In the endometrial epithelium, we have previously shown that ARID1A normally promotes epithelial identity by repressing the expression of mesenchymal and invasion genes, at least in part through promoter-proximal and distal chromatin interactions that affect transcriptional activity (Reske et al, 2020; Wilson et al, 2020; Wilson et al, 2019). Other reports have demonstrated that ARID1A and SWI/SNF can function as a repressor, often through interactions with repressive machinery (Bui et al, 2019; Chandler et al, 2013; Rafati et al, 2011; Van Rechem, Boulay, & Leprince, 2009). Although nucleosome structure and histone post-translational modifications are suspected mechanisms, it remains poorly understood how SWI/SNF governs the epigenome.…”